Changing the number of times that you can undo an operation to a lower number can decrease the amount of required memory. The default setting is unlimited.

1. On the Edit menu, click Preferences.
2. In the Preferences dialog box, click the Miscellaneous tab.
3. In the Undo section, specify one of the following:
   • To specify an unlimited number of times that you can undo and redo operations, click Unlimited.
   • To specify the maximum number of times that you can undo and redo operations, click Limited to, and specify the number of operations.